MOPPET® Compressor Valve

MOPPET valves provide outstanding reliability, even in the most demanding service. Optimized for each application, the MOPPET valve delivers consistently longer run times and reduces total life cycle costs.

Robust, Radiused-Disc Elements

A MOPPET valve consists of a series of small, identical, radiused-disc elements that operate independently of each other. Each element is made of durable, lightweight thermoplastic material.

The element design provides outstanding resistance to damage and wear from entrained debris.

  • The low mass of the thermoplastic disc reduces impact velocities
  • The radiused sealing surface deflects debris
  • The thickness of the elements and small centerline diameter make them extremely stiff and resilient to high impact forces caused by extreme pressure, gas mole weight, driver speed, or the presence of incompressible matter in the gas

Advanced Spring Design

Springs and spring pockets in MOPPET valves are designed for extended performance in dirty service.

  • Spring pockets have generous vent holes that eliminate build-up of incompressible materials that can damage springs
  • High lifts and more space between the spring coils allow debris to pass freely through the valve
  • Springs have significantly taller free length, allowing for large wire diameter that reduces torsional stress and makes the springs more resistant to damage from debris

Durable in Any Service

MOPPET valves meet NACE specifications and can be used in almost any service.

MOPPET cartridges are precision-manufactured from 17-4 stainless steel for exceptional corrosion resistance on critical seating surfaces. Thermoplastic internal components are injection-molded in-house from the highest grade raw materials.

Valves Achieve Run Time Target in Demanding Gas Gathering Application

Field Repairs in Minutes

MOPPET valves make repairs simple and economical. Worn cartridges can be removed and replaced in minutes with a hydraulic press. Repairs can be performed in the field, with no lapping, grinding or machining required.

Elements and springs are replaced each time a valve is serviced, but cartridges are replaced only when damaged or worn. Incremental replacement reduces costs and helps maximize the utility of each component.

Economical Inventory

MOPPET cartridges are identical and universally interchangeable – from valve to valve and compressor to compressor. This commonality of parts significantly reduces inventory costs. Repair technicians remain fully prepared with only a minimal number of spare parts on-hand.


  • Superior reliability
  • Rugged construction
  • Commonality of parts from one compressor to the next
  • Incremental cartridge replacement
  • Wide application range
  • Simple, on-site repair using only a hydraulic press
  • Available with finger and plug unloaders

U.S. Patent No. 5,511,583; other patents worldwide.

MOPPET® Compressor Valve Information Sheet

Extend Run Times Further with Elastomer-Enhanced Moppet Valve Elements

Moppet Valve 1
Moppet valve